Developmentally regulated conversion of surface-exposed chitin to chitosan in cell walls of plant pathogenic fungi
Developmentally regulated conversion of surface-exposed chitin to chitosan in cell walls of plant pathogenic fungi
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DOI：
10.1046/j.1469-8137.2002.00487.x
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发表时间：
2002-10-01
期刊：
影响因子：
9.4
通讯作者：
Deising, HB
中科院分区：
文献类型：
--
作者：
El Gueddari, NE;Rauchhaus, U;Deising, HB
小麦杆锈菌（Puccinia graminis f.）本文研究了小麦锈病病原菌、蚕豆锈菌和玉米炭疽病病原菌--禾生炭疽菌（Colletotrichum graminicola）的侵染过程。用荧光标记的凝集素小麦胚芽凝集素（WGA）进行落射荧光显微镜观察，发现在植物角质层上形成的侵染结构表面暴露几丁质，而在侵入寄主后形成的结构表面则不暴露几丁质。为了鉴定几丁质通过去N-乙酰化修饰，我们提出了特异性识别脱-N-乙酰化壳聚糖的多克隆抗体。这些抗体只标记那些感染的结构内分化的植物，表明壳聚糖是暴露在细胞壁表面后penetration.Surface改性的真菌细胞壁几丁质脱N-乙酰化被讨论作为真菌的策略，以保护细胞壁的致病性菌丝酶水解宿主几丁质酶，并避免在入侵的宿主组织中产生的自催化防御反应系统。
Conversion of surface-exposed chitin to chitosan in cell walls of in vitro - and in vivo-differentiated infection structures of two rust fungi, the wheat stem rust fungus Puccinia graminis f. sp. tritici and the broad bean rust fungus Uromyces fabae, and of the causal agent of maize anthracnose, Colletotrichum graminicola, were studied.Epi-fluorescence microscopy with the fluorescence-labeled lectin wheat germ agglutinin (WGA) revealed that surfaces of infection structures formed on the plant cuticle expose chitin, whereas surfaces of structures formed after invading the host do not.To identify chitin modification by de-N-acetylation, we raised polyclonal antibodies specifically recognizing de-N-acetylated chitosan. These antibodies labeled only those infection structures that differentiate inside the plant, indicating that chitosan is exposed on cell wall surfaces post penetration.Surface modification of the fungal cell walls by chitin de-N-acetylation is discussed as a fungal strategy to protect cell walls of pathogenic hyphae from enzymatic hydrolysis by host chitinases, and to avoid generation of an auto-catalytic defense response system in the invaded host tissue.